高濃度残留塩素水によるNBRの劣化現象とその劣化メカニズム The Degradation Mechanism of NBR Invaded by High Concentration Chlorine Water
In order to elucidate the degradation behavior of NBR caused by high concentration chlorine water, NBR samples corroded in 200ppm chlorine water and in pure water were analyzed by means of EPMA, FT-IR and XPS. The degradation process of the NBR corroded in high concentration chlorine water is considered as follows: (1) an α-H of the butadiene double bond in NBR molecule is subject to substitution by chlorine; (2) the chlorinated NBR abstracts an α-H in another NBR molecule to cause the elimination of HCl, which generates polymer radicals; (3) the polymer radicals thus produced add to polybutadiene double-bonds in the other NBR. It is concluded that residual chlorine reacts with NBR by chlorination and oxidation mechanisms and that these reactions lead to hardening and degradation of NBR through the increase in the crosslinking density.
日本ゴム協會誌 78(3), 98-102, 2005-03-15